**5. Discussion**

There have been many studies presenting MCDM models using fuzzy set theory to evaluate and select the location of a renewable energy plant, particularly solar energy. However, the literature review shows that most of these studies only use economic, or technological, or site characteristics, or environmental or social standards to assess potential locations. There are few studies that simultaneously use economic, technological, site characteristics, environmental and social factor standards in the process of location selection. In addition, there seems to be no research on developing an MCDM model to choose a location for a solar power plant in the Mekong Delta.

This is a reason the author proposed an MCDM model including data envelopment analysis (DEA) and fuzzy analytical network process (FANP) for solar power plant location selection in Mekong Delta, Vietnam in this work. In the first step, some potential location is selected from 13 location in Mekong Delta by using the DEA model. Then, the FANP model is applied for rank potential sites. In a renewable energy project, location decision is the most importance activity; location decision is always a multicriteria decision making factor, as the decision maker must consider both quantitative and qualitative factors. In any renewable energy project, location decision is a very important decision, decision maker must consider qualitative and quantitative factors. Thus, solar power plant location selection is a multicriteria decision making (MCDM). For selection optimal location, the proposed model considered five main factors: economic factors (construction cost, operation and managemen<sup>t</sup> cost, new feeder cost), technological factors (distance from major road, distance from power network, potential demand), site characteristics factors (ecology, elevation, approachability), environmental factors (temperature, sunshine hours, humidity) and social factors (supports mechanisms, protection law and legal regulatory compliance) As per the results shown in Table 9, Ben Tre (DEL03) is the optimal solution for investing solar power plants in Mekong Delta, Vietnam.

**Table 9.** Final ranking from the FANP model.

